Orthopedic supports are available in many forms. A common orthopedic support is a rigid knee brace worn by persons who suffer knee instabilities and by those engaged in sporting activities to prevent injuries to the knee. A common purpose of the knee brace is to provide exterior support for the knee to prevent any unnatural movements of the knee joints which could injure or reinjure the knee ligaments, while allowing the normal swinging movement of the knee joint. Such knee braces are commonly used for post-operative patients who have had knee surgery. These knee braces commonly include metal bars and pivot joints to provide a rigid means of support. Such knee braces are sold by a physician's prescription only and require a skilled orthotist to fit them properly to the patient.
Other orthopedic supports are the so-called "soft supports" which are sold in drug stores, hospitals and doctors' offices. The soft supports provide a modest amount of support for an injured joint. These types of supports do not include rigid metal bars or stays, but are simply made from a soft, stretchable material. They are often purchased without a prescription or the need for skilled professional fitting. The soft orthopedic supports have been used for a number of years and have been commonly available as supports for the knee, ankle, thigh, wrist, elbow, chest or lower back. These soft orthopedic supports are normally worn for sprains and strains, arthritis, tendonitis, bursitis, inflammation, or to reduce discomfort during post-operative use or to treat post-trauma discomfort.
The soft-orthopedic supports are often made from neoprene rubber (i.e. polychloroprene). This material is desirable because of its combination of favorable properties useful in orthopedic supports. Neoprene rubber has good elasticity and a relatively high density, properties which combine to provide good compression support and resistance to shear forces.
Neoprene rubber is a closed cell material and therefore does not dissipate heat very well during use. Its closed cell characteristics can be useful in retaining heat during use by reflecting emitted heat back into the bones and joints of the affected area. This localized concentration of heat can aid venous flow, help reduce edema, and make the soft tissues less susceptible to injury.
Although use of neoprene rubber in orthopedic supports can be useful because of its ability to concentrate heat, the natural tendency of the closed cell material to prevent heat dissipation creates problems for the user. The neoprene rubber supports are stretched when applied so that the material can compress around the affected area. This tight compression fit, combined with the high density of the material and the lack of air circulation and dissipation through the material, causes heat discomfort and perspiration and often leads to heat rashes. Prolonged use of such neoprene rubber supports can cause the user to perspirate constantly, causing discomfort to such a degree that the user often stops wearing the support prematurely. In effect, the material itself dictates the length of time that the orthopedic supports can be worn. It is not uncommon for users to stop wearing such supports after about one to two hours.
Replacing the closed cell neoprene rubber with an open cell material does not provide an acceptable solution to the heat discomfort problem. Open cell materials, such as sponge rubber or plastic foam materials such as high density polyester or polyurethane foams, are materials characterized by their ability to "breathe". That is, they are porous to air and water. Such materials can ensure good air circulation and good heat dissipation and absorption of body fluids during use. However, such open cell materials do not inherently possess the high density necessary for the materials to provide sufficient compressive strength to serve as an orthopedic support.
Thus, there is a need for an orthopedic support having sufficient elasticity and density to offer a necessary level of compression support, while also dissipating heat during use sufficient to avoid undue perspiration and heat discomfort during prolonged use of the support.